Using action cameras to assess habitat use by Pseudobarbus afer and Sandelia capensis in the Swartkops River, Eastern Cape, South Africa
- Authors: Hannweg, Bianca
- Date: 2018
- Subjects: Freshwater biodiversity -- South Africa -- Eastern Cape , Freshwater biodiversity conservation -- South Africa -- Eastern Cape , Freshwater ecology -- South Africa -- Eastern Cape , Freshwater fishes -- South Africa -- Eastern Cape , Freshwater fishes -- Behavior -- South Africa -- Eastern Cape , Freshwater fishes -- Habitat -- South Africa -- Eastern Cape , Underwater videography , Anabantidae -- South Africa -- Eastern Cape , Cyprinidae -- South Africa -- Eastern Cape , Pseudobarbus afer , Sandelia capensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62039 , vital:28098
- Description: Currently, freshwater systems are facing various threats, freshwater biota are declining and there is an increased need to monitor freshwater fauna and flora using non-invasive methods. This thesis aimed to evaluate the potential of using action cameras as a tool for the monitoring of freshwater fish populations and the collection of habitat utilisation data. This evaluation was conducted in headwater tributaries of the Swartkops River in South Africa, using two threatened species that have not been extensively studied, Pseudobarbus afer (Peters, 1864) and Sandelia capensis (Cuvier, 1831). The aims of this study were to: (1) assess the use of underwater video analysis (UWVA) using action cameras (videos and still photographs) in comparison to estimates derived from snorkel surveys, to estimate the abundance of P. afer in headwater streams; (2) use estimates derived from UWVA (videos and photographs) to assess the habitat use of two imperilled species, P. afer and S. capensis; and (3) assess habitat use by these two species in the presence of an artificial habitat. This work demonstrated that: (1) estimates derived from videos and photographs were strongly correlated to estimates derived from snorkel surveys, provided multiple cameras were used; (2) estimates derived from videos and photographs were not significantly different to estimates derived from snorkel surveys; (3) a filming period of 15 minutes was sufficient at detecting 0.9 of the cumulative mMaxN (mean MaxN) within one of the five habitats; and (4) still photographs, which are less time consuming to process than videos, could be used in preference to videos. Based on these findings, techniques using action cameras to assess habitat utilisation and behaviour in situ of the two-focal species, were developed using six habitat types (inflow, outflow, woody debris, fern root, middle and artificial) in four pools. It was demonstrated that: (1) there was a significant difference in proportional occupancies across habitats for both P. afer and S. capensis; (2) Pseudobarbus afer were mainly observed schooling in the middle of the pool and feeding on detritus material in fern root, woody debris and off the artificial structure; and (3) Sandelia capensis rapidly colonised the artificial structure and were observed utilising it for refuge. In conclusion, this work demonstrated that still photographs from action cameras can be used in place of videos to estimate the abundance of freshwater fishes and assess their habitat use and behaviour in clear headwater streams. This work also demonstrated how action cameras could be used to evaluate the effect of the introduction of artificial habitat as a restoration measure for headwater fish communities.
- Full Text:
- Date Issued: 2018
- Authors: Hannweg, Bianca
- Date: 2018
- Subjects: Freshwater biodiversity -- South Africa -- Eastern Cape , Freshwater biodiversity conservation -- South Africa -- Eastern Cape , Freshwater ecology -- South Africa -- Eastern Cape , Freshwater fishes -- South Africa -- Eastern Cape , Freshwater fishes -- Behavior -- South Africa -- Eastern Cape , Freshwater fishes -- Habitat -- South Africa -- Eastern Cape , Underwater videography , Anabantidae -- South Africa -- Eastern Cape , Cyprinidae -- South Africa -- Eastern Cape , Pseudobarbus afer , Sandelia capensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62039 , vital:28098
- Description: Currently, freshwater systems are facing various threats, freshwater biota are declining and there is an increased need to monitor freshwater fauna and flora using non-invasive methods. This thesis aimed to evaluate the potential of using action cameras as a tool for the monitoring of freshwater fish populations and the collection of habitat utilisation data. This evaluation was conducted in headwater tributaries of the Swartkops River in South Africa, using two threatened species that have not been extensively studied, Pseudobarbus afer (Peters, 1864) and Sandelia capensis (Cuvier, 1831). The aims of this study were to: (1) assess the use of underwater video analysis (UWVA) using action cameras (videos and still photographs) in comparison to estimates derived from snorkel surveys, to estimate the abundance of P. afer in headwater streams; (2) use estimates derived from UWVA (videos and photographs) to assess the habitat use of two imperilled species, P. afer and S. capensis; and (3) assess habitat use by these two species in the presence of an artificial habitat. This work demonstrated that: (1) estimates derived from videos and photographs were strongly correlated to estimates derived from snorkel surveys, provided multiple cameras were used; (2) estimates derived from videos and photographs were not significantly different to estimates derived from snorkel surveys; (3) a filming period of 15 minutes was sufficient at detecting 0.9 of the cumulative mMaxN (mean MaxN) within one of the five habitats; and (4) still photographs, which are less time consuming to process than videos, could be used in preference to videos. Based on these findings, techniques using action cameras to assess habitat utilisation and behaviour in situ of the two-focal species, were developed using six habitat types (inflow, outflow, woody debris, fern root, middle and artificial) in four pools. It was demonstrated that: (1) there was a significant difference in proportional occupancies across habitats for both P. afer and S. capensis; (2) Pseudobarbus afer were mainly observed schooling in the middle of the pool and feeding on detritus material in fern root, woody debris and off the artificial structure; and (3) Sandelia capensis rapidly colonised the artificial structure and were observed utilising it for refuge. In conclusion, this work demonstrated that still photographs from action cameras can be used in place of videos to estimate the abundance of freshwater fishes and assess their habitat use and behaviour in clear headwater streams. This work also demonstrated how action cameras could be used to evaluate the effect of the introduction of artificial habitat as a restoration measure for headwater fish communities.
- Full Text:
- Date Issued: 2018
Using aspects of game theory for enhanced stakeholder participation perspectives in integrated water resource management: a Kat River Valley case study
- Authors: Mbatha, Cyril
- Date: 2005
- Subjects: Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:971 , http://hdl.handle.net/10962/d1002705 , Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Description: South Africa is a water poor region and yet, like in many other developing countries, water resources are a valuable production input in socially important industries such as agriculture and mining (Nieuwoudt et al., 2004:162-182). With a mean annual rainfall and runoff of 502mm and 42mm (420m³ per hectare per annum) respectively, Briers and Powell (1993:1) speculate that water shortages will limit South Africa’s economic development in the twenty-first century. In response to the challenges of water resource scarcity and socio-economic inequalities, in 1997 the South African Department of Water Affairs and Forestry (DWAF), following international trends, formulated a National Water Policy (NWP) based on Integrated Water Resource Management (IWRM) principles (Palmer et al., 2003). The main objectives of the NWP (1997) are to protect national water resources from degradation, provide economically disadvantaged communities with access to water resources and promote economic development, through the devolution of water management responsibilities to locally established water institutions (NWP, 1997). The pursuit of these objectives requires a thorough investigation of biophysical, sociopolitical and economic characteristics of the demarcated water areas. For such an investigation to provide accurate and locally relevant results, broad stakeholder participation is of paramount importance. The thesis discusses economic measures required in pursuing enhanced stakeholder participation levels at local levels. A socio-economic survey investigation describing major participation trends against reported property rights and Willingness to Pay values was conducted in the Kat River Valley, Eastern Cape province. From the investigation, observed participation trends driven by economic interests were identified and used in recommendations proposed for the policy implementation process. Using game theoretic arguments as guidelines in soliciting cooperative behaviour in the use and consumption of common resources (Ostrom, 1990), the thesis proposes the introduction of water related public works projects as employment creating vehicles for individuals and communities targeted for economic empowerment and participation in the water policy. However, for sustainable stakeholder participation levels, it is argued that the employment positions created through the projects need to be designed in a manner that would encourage an evolution of long-term relationships between stakeholders and the water management institutions.
- Full Text:
- Date Issued: 2005
- Authors: Mbatha, Cyril
- Date: 2005
- Subjects: Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:971 , http://hdl.handle.net/10962/d1002705 , Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Description: South Africa is a water poor region and yet, like in many other developing countries, water resources are a valuable production input in socially important industries such as agriculture and mining (Nieuwoudt et al., 2004:162-182). With a mean annual rainfall and runoff of 502mm and 42mm (420m³ per hectare per annum) respectively, Briers and Powell (1993:1) speculate that water shortages will limit South Africa’s economic development in the twenty-first century. In response to the challenges of water resource scarcity and socio-economic inequalities, in 1997 the South African Department of Water Affairs and Forestry (DWAF), following international trends, formulated a National Water Policy (NWP) based on Integrated Water Resource Management (IWRM) principles (Palmer et al., 2003). The main objectives of the NWP (1997) are to protect national water resources from degradation, provide economically disadvantaged communities with access to water resources and promote economic development, through the devolution of water management responsibilities to locally established water institutions (NWP, 1997). The pursuit of these objectives requires a thorough investigation of biophysical, sociopolitical and economic characteristics of the demarcated water areas. For such an investigation to provide accurate and locally relevant results, broad stakeholder participation is of paramount importance. The thesis discusses economic measures required in pursuing enhanced stakeholder participation levels at local levels. A socio-economic survey investigation describing major participation trends against reported property rights and Willingness to Pay values was conducted in the Kat River Valley, Eastern Cape province. From the investigation, observed participation trends driven by economic interests were identified and used in recommendations proposed for the policy implementation process. Using game theoretic arguments as guidelines in soliciting cooperative behaviour in the use and consumption of common resources (Ostrom, 1990), the thesis proposes the introduction of water related public works projects as employment creating vehicles for individuals and communities targeted for economic empowerment and participation in the water policy. However, for sustainable stakeholder participation levels, it is argued that the employment positions created through the projects need to be designed in a manner that would encourage an evolution of long-term relationships between stakeholders and the water management institutions.
- Full Text:
- Date Issued: 2005
Using bioinformatics tools to screen for trypanosomal cathepsin B cysteine protease inhibitors from the SANCDB as a novel therapeutic modality against Human African Trypanosomiasis (HAT)
- Authors: Mokhawa, Gaone
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3304 , vital:20470
- Description: Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a fatal chronic disease that is caused by flagellated protozoans, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. HAT is spread by a bite from an infected tsetse fly of the Glosina genus. Up to 60 million people in 36 countries in sub-Saharan Africa are at a risk of infection from HAT with up to 30 000 deaths reported every year. Current chemotherapy for HAT is insufficient since the available drugs exhibit unacceptable side effects (toxicity) and parasite resistance. Novel treatments and approaches for development of specific and more potent drugs for HAT are therefore required. One approach is to target vital proteins that are essential to the life cycle of the parasite. The main interest of this study is to explore Trypanosoma brucei cathepsin B-like protease (TbCatB) structural and functional properties with the primary goal of discovering non peptide small molecule inhibitors of TbCatB using bioinformatics approaches. TbCatB is a papain family C1 cysteine protease which belongs to clan CA group and it has emerged as a potential HAT drug target. Papain family cysteine proteases of Clan CA group of Trypanosoma brucei (rhodesain and TbCatB) have demonstrated potential as chemotherapeutic targets using synthetic protease inhibitors like Z-Phe-Ala-CHN2 to kill the parasite in vitro and in vivo. TbCatB has been identified as the essential cysteine protease of T. brucei since mRNA silencing of TbCatB killed the parasite and resulted in a cure in mice infected with T. brucei while mRNA silencing of rhodesain only extended mice life. TbCatB is therefore a promising drug target against HAT and the discovery and development of compounds that can selectively inhibit TbCatB without posing any danger to the human host represent a great therapeutic solution for treatment of HAT. To understand protein-inhibitor interactions, useful information can be obtained from high resolution protease-inhibitor crystal structure complexes. This study aims to use bioinformatics approaches to carry out comparative sequence, structural and functional analysis of TbCatB protease and its homologs from T. congolense, T, cruzi, T. vivax and H. sapien as well as to identify non-peptide small molecule inhibitors of TbCatB cysteine proteases from natural compounds of South African origin. Sequences of TbCatB (PDB ID: 3HHI) homologs were retrieved by a BLAST search. Human cathepsin B (PDB ID: 3CBJ) was selected from a list of templates for homology modelling found by HHpred. MODELLER version 9.10 program was used to generate a hundred models for T. congolense, T, cruzi and T. vivax cathepsin B like proteases using 3HHI and 3CBJ as templates. The best models were chosen based on their low DOPE Z scores before validation using MetaMQAPII, ANOLEA, PROCHECK and QMEAN6. The DOPE Z scores and the RMSD (RMS) values of the calculated models indicate that the models are of acceptable energy (stability) and fold (conformation). Results from the different MQAPs indicate the models are of acceptable quality and they can be used for docking studies. High throughput screening of SANCDB using AutoDock Vina revealed nine compounds, SANC00 478, 479, 480, 481, 482, 488, 489, 490 and 491, having a strong affinity for Trypanosoma spp. cathepsin B proteases than HsCatB. SANC00488 has the strongest binding to Trypanosoma spp. cathepsin B proteases and the weakest binding to HsCatB protease. Molecular dynamics (MD) simulations show that the complexes between SANC00488 and TbCatB, TcCatB, TcrCatB and TvCatB are stable and do not come apart during simulation. The complex between this compound and HsCatB however is unstable and comes apart during simulation. Residues that are important for the stability of SANC00488-TbCatB complex are Gly328 of the S2 subsite, Phe208, and Ala256. In conclusion SANC00488 is a good candidate for development of a drug against HAT.
- Full Text:
- Date Issued: 2016
- Authors: Mokhawa, Gaone
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3304 , vital:20470
- Description: Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a fatal chronic disease that is caused by flagellated protozoans, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. HAT is spread by a bite from an infected tsetse fly of the Glosina genus. Up to 60 million people in 36 countries in sub-Saharan Africa are at a risk of infection from HAT with up to 30 000 deaths reported every year. Current chemotherapy for HAT is insufficient since the available drugs exhibit unacceptable side effects (toxicity) and parasite resistance. Novel treatments and approaches for development of specific and more potent drugs for HAT are therefore required. One approach is to target vital proteins that are essential to the life cycle of the parasite. The main interest of this study is to explore Trypanosoma brucei cathepsin B-like protease (TbCatB) structural and functional properties with the primary goal of discovering non peptide small molecule inhibitors of TbCatB using bioinformatics approaches. TbCatB is a papain family C1 cysteine protease which belongs to clan CA group and it has emerged as a potential HAT drug target. Papain family cysteine proteases of Clan CA group of Trypanosoma brucei (rhodesain and TbCatB) have demonstrated potential as chemotherapeutic targets using synthetic protease inhibitors like Z-Phe-Ala-CHN2 to kill the parasite in vitro and in vivo. TbCatB has been identified as the essential cysteine protease of T. brucei since mRNA silencing of TbCatB killed the parasite and resulted in a cure in mice infected with T. brucei while mRNA silencing of rhodesain only extended mice life. TbCatB is therefore a promising drug target against HAT and the discovery and development of compounds that can selectively inhibit TbCatB without posing any danger to the human host represent a great therapeutic solution for treatment of HAT. To understand protein-inhibitor interactions, useful information can be obtained from high resolution protease-inhibitor crystal structure complexes. This study aims to use bioinformatics approaches to carry out comparative sequence, structural and functional analysis of TbCatB protease and its homologs from T. congolense, T, cruzi, T. vivax and H. sapien as well as to identify non-peptide small molecule inhibitors of TbCatB cysteine proteases from natural compounds of South African origin. Sequences of TbCatB (PDB ID: 3HHI) homologs were retrieved by a BLAST search. Human cathepsin B (PDB ID: 3CBJ) was selected from a list of templates for homology modelling found by HHpred. MODELLER version 9.10 program was used to generate a hundred models for T. congolense, T, cruzi and T. vivax cathepsin B like proteases using 3HHI and 3CBJ as templates. The best models were chosen based on their low DOPE Z scores before validation using MetaMQAPII, ANOLEA, PROCHECK and QMEAN6. The DOPE Z scores and the RMSD (RMS) values of the calculated models indicate that the models are of acceptable energy (stability) and fold (conformation). Results from the different MQAPs indicate the models are of acceptable quality and they can be used for docking studies. High throughput screening of SANCDB using AutoDock Vina revealed nine compounds, SANC00 478, 479, 480, 481, 482, 488, 489, 490 and 491, having a strong affinity for Trypanosoma spp. cathepsin B proteases than HsCatB. SANC00488 has the strongest binding to Trypanosoma spp. cathepsin B proteases and the weakest binding to HsCatB protease. Molecular dynamics (MD) simulations show that the complexes between SANC00488 and TbCatB, TcCatB, TcrCatB and TvCatB are stable and do not come apart during simulation. The complex between this compound and HsCatB however is unstable and comes apart during simulation. Residues that are important for the stability of SANC00488-TbCatB complex are Gly328 of the S2 subsite, Phe208, and Ala256. In conclusion SANC00488 is a good candidate for development of a drug against HAT.
- Full Text:
- Date Issued: 2016
Using captive seabirds to assess knowledge gaps in stable isotope analysis of diets
- Authors: Micklem, Isabel Andrea
- Date: 2019
- Subjects: Stable isotopes -- Analysis African penguin -- South Africa Breeding
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/65101 , vital:28686
- Description: Stable isotope (SI) ratios of carbon (δ13C) and nitrogen (δ15N) are now widely used as biomarkers in ecological studies to provide information about food web structuring. However, understanding trophic relationships using SI analysis requires not only knowledge of SI values of predator and prey, but also accurate discrimination factors (DFs), which can differ among species and by physiological state. This thesis examined three questions using captive birds from the South African Foundation for the Conservation of Coastal Birds (SANCCOB). First, the effects of ontogeny on δ13C and δ15N ratios of African penguins (Spheniscus demersus) were assessed. Blood samples were collected from penguins in four age classes (P3 chicks, blues, juveniles and adults) concurrently with their diet (sardine (Sardinops sagax) and formula). Second, to assess the influence of breeding physiology on SI ratios, the blood of ten breeding pairs of penguins was sampled over a five-month period from June to October 2016. Following laying, each pair was categorised into one of three (four for whole blood) egg production phases (initial yolk deposition, rapid yolk deposition and post-laying) and their influences on SI ratios were tested. Third, species differences in DFs were evaluated for African penguins, kelp and Hartlaub’s gulls (Larus dominicanus and L. hartlaubii), greater crested terns (Thalasseus bergii) and Cape cormorants (Phalacrocorax capensis). Flying birds were mostly fed sardine with a small but unknown amount of sardinella (Sardinella aurita), DFs were therefore estimated for a 50:50 sardine:sardinella diet, a 75:25 sardine:sardinella diet and a 100% sardine diet for each flying bird species. The DFs were assessed for the whole blood (WB), red blood cells (RBC), plasma (PL) and delipidated plasma of the penguins, and only WB for the flying birds as well as flesh, whole fish, delipidated flesh and delipidated whole fish for fish species, and for formula. Results indicated that age influenced both the δ13C and δ15N of WB, only the δ15N of RBC and the δ13C of delipidated PL. The assessment of breeding physiology yielded a significant interaction between the effects of egg production phase and sex on the δ13C of WB; females had significantly lower δ13C in the rapid yolk deposition phase than the other two phases and all males. The δ13C of PL was affected only by sex, with females having a significantly lower δ13C value than males. Neither physiological state nor sex influenced the other blood components. Differences were found among the three DFs in the non-penguin species, but not for all consumer – prey tissue combinations. There were also significant differences among species with a DF calculated from a diet with the most probable prey proportions eaten. Depending on the combination of consumer and prey tissue used to calculate the DF, a different conclusion regarding trophic information can be reached. A literature review updated with the present data showed that no general pattern or grouping of similar species with regards to DF values could be drawn, highlighting the importance of determining species- and tissue-specific DFs. Thus age, egg production, tissue and species all influenced the SI values of bird blood and therefore their DFs. Not all physiological conditions affect all blood components in the same way, making different components more or less sensitive to physiological influences. Though their influence is at a small enough scale that it is unlikely to hamper correct conclusion in ecological studies, it is crucial that these factors are considered when using SI analysis (SIA). When uncertainties exist for some coefficients in wild studies, SIA should therefore be combined to other dietary techniques to determine the food web structure as best as possible.
- Full Text:
- Date Issued: 2019
- Authors: Micklem, Isabel Andrea
- Date: 2019
- Subjects: Stable isotopes -- Analysis African penguin -- South Africa Breeding
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/65101 , vital:28686
- Description: Stable isotope (SI) ratios of carbon (δ13C) and nitrogen (δ15N) are now widely used as biomarkers in ecological studies to provide information about food web structuring. However, understanding trophic relationships using SI analysis requires not only knowledge of SI values of predator and prey, but also accurate discrimination factors (DFs), which can differ among species and by physiological state. This thesis examined three questions using captive birds from the South African Foundation for the Conservation of Coastal Birds (SANCCOB). First, the effects of ontogeny on δ13C and δ15N ratios of African penguins (Spheniscus demersus) were assessed. Blood samples were collected from penguins in four age classes (P3 chicks, blues, juveniles and adults) concurrently with their diet (sardine (Sardinops sagax) and formula). Second, to assess the influence of breeding physiology on SI ratios, the blood of ten breeding pairs of penguins was sampled over a five-month period from June to October 2016. Following laying, each pair was categorised into one of three (four for whole blood) egg production phases (initial yolk deposition, rapid yolk deposition and post-laying) and their influences on SI ratios were tested. Third, species differences in DFs were evaluated for African penguins, kelp and Hartlaub’s gulls (Larus dominicanus and L. hartlaubii), greater crested terns (Thalasseus bergii) and Cape cormorants (Phalacrocorax capensis). Flying birds were mostly fed sardine with a small but unknown amount of sardinella (Sardinella aurita), DFs were therefore estimated for a 50:50 sardine:sardinella diet, a 75:25 sardine:sardinella diet and a 100% sardine diet for each flying bird species. The DFs were assessed for the whole blood (WB), red blood cells (RBC), plasma (PL) and delipidated plasma of the penguins, and only WB for the flying birds as well as flesh, whole fish, delipidated flesh and delipidated whole fish for fish species, and for formula. Results indicated that age influenced both the δ13C and δ15N of WB, only the δ15N of RBC and the δ13C of delipidated PL. The assessment of breeding physiology yielded a significant interaction between the effects of egg production phase and sex on the δ13C of WB; females had significantly lower δ13C in the rapid yolk deposition phase than the other two phases and all males. The δ13C of PL was affected only by sex, with females having a significantly lower δ13C value than males. Neither physiological state nor sex influenced the other blood components. Differences were found among the three DFs in the non-penguin species, but not for all consumer – prey tissue combinations. There were also significant differences among species with a DF calculated from a diet with the most probable prey proportions eaten. Depending on the combination of consumer and prey tissue used to calculate the DF, a different conclusion regarding trophic information can be reached. A literature review updated with the present data showed that no general pattern or grouping of similar species with regards to DF values could be drawn, highlighting the importance of determining species- and tissue-specific DFs. Thus age, egg production, tissue and species all influenced the SI values of bird blood and therefore their DFs. Not all physiological conditions affect all blood components in the same way, making different components more or less sensitive to physiological influences. Though their influence is at a small enough scale that it is unlikely to hamper correct conclusion in ecological studies, it is crucial that these factors are considered when using SI analysis (SIA). When uncertainties exist for some coefficients in wild studies, SIA should therefore be combined to other dietary techniques to determine the food web structure as best as possible.
- Full Text:
- Date Issued: 2019
Using co-located radars and instruments to analyse ionespheric events over South Africa
- Authors: Athieno, Racheal
- Date: 2012
- Subjects: Ionosphere -- Research -- South Africa , Space environment -- Research -- South Africa , Meteorology -- Research -- South Africa , Ionosondes -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5493 , http://hdl.handle.net/10962/d1005279 , Ionosphere -- Research -- South Africa , Space environment -- Research -- South Africa , Meteorology -- Research -- South Africa , Ionosondes -- Research -- South Africa
- Description: Space weather and its effect on technological systems are important for scientific research. Developing an understanding of the behaviour, sources and effects of ionospheric events form a basis for improving space weather prediction. This thesis attempts to use co-located radars and instruments for the analysis of ionospheric events over South Africa. The HF Doppler radar, ionosonde, Global Positioning System (GPS) and GPS ionospheric scintillation monitor (GISTM) receivers are co-located in Hermanus (34.4°S, 19.2°E), one of the observatories for the space science directorate of the South African National Space Agency (SANSA). Data was obtained from these radars and instruments and analysed for ionospheric events. Only the Hermanus station was selected for this analysis, because it is currently the only South African station that hosts all the mentioned radars and instruments. Ionospheric events identified include wave-like structures, Doppler spread, sudden frequency deviations and ionospheric oscillations associated with geomagnetic pulsations. For the purpose of this work, ionospheric events are defined as any unusual structures observed on the received signal and inferred from observations made by the HF Doppler radar. They were identified by visual inspection of the Doppler shift spectrograms. The magnitude and nature of the events vary, depending on their source and were observed by all, some or one instrument. This study suggests that the inclusion of a wider data coverage and more stations in South Africa merit consideration, especially since plans are underway to host a co-located radar network similar to that in Hermanus at at least three additional observatory sites in South Africa. This study lays a foundation for multi-station co-located radar and instrument observation and analysis of ionospheric events which should enhance the accuracy of space weather and HF communication prediction.
- Full Text:
- Date Issued: 2012
- Authors: Athieno, Racheal
- Date: 2012
- Subjects: Ionosphere -- Research -- South Africa , Space environment -- Research -- South Africa , Meteorology -- Research -- South Africa , Ionosondes -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5493 , http://hdl.handle.net/10962/d1005279 , Ionosphere -- Research -- South Africa , Space environment -- Research -- South Africa , Meteorology -- Research -- South Africa , Ionosondes -- Research -- South Africa
- Description: Space weather and its effect on technological systems are important for scientific research. Developing an understanding of the behaviour, sources and effects of ionospheric events form a basis for improving space weather prediction. This thesis attempts to use co-located radars and instruments for the analysis of ionospheric events over South Africa. The HF Doppler radar, ionosonde, Global Positioning System (GPS) and GPS ionospheric scintillation monitor (GISTM) receivers are co-located in Hermanus (34.4°S, 19.2°E), one of the observatories for the space science directorate of the South African National Space Agency (SANSA). Data was obtained from these radars and instruments and analysed for ionospheric events. Only the Hermanus station was selected for this analysis, because it is currently the only South African station that hosts all the mentioned radars and instruments. Ionospheric events identified include wave-like structures, Doppler spread, sudden frequency deviations and ionospheric oscillations associated with geomagnetic pulsations. For the purpose of this work, ionospheric events are defined as any unusual structures observed on the received signal and inferred from observations made by the HF Doppler radar. They were identified by visual inspection of the Doppler shift spectrograms. The magnitude and nature of the events vary, depending on their source and were observed by all, some or one instrument. This study suggests that the inclusion of a wider data coverage and more stations in South Africa merit consideration, especially since plans are underway to host a co-located radar network similar to that in Hermanus at at least three additional observatory sites in South Africa. This study lays a foundation for multi-station co-located radar and instrument observation and analysis of ionospheric events which should enhance the accuracy of space weather and HF communication prediction.
- Full Text:
- Date Issued: 2012
Using experiential learning to facilitate pharmacy students' understanding of patients' medication practice in chronic illness
- Authors: Williams, Kevin
- Date: 2006
- Subjects: Chronic diseases -- Chemotherapy Chronically ill -- Care Pharmacy -- Study and teaching Pharmacy -- Practice Social medicine Health -- Sociological aspects Diseases -- Sociological aspects Health -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1322 , http://hdl.handle.net/10962/d1003955
- Description: This study originates from experiences which led me to question the way pharmacists are equipped to advise and support the medicine-taking practice of patients using chronic medication. The study offers a critical theoretical consideration of underlying perspectives informing pharmacy education. I propose following a critical realist ontological perspective, a social realist understanding of social structure and human agency, and a sociocultural epistemology. Based on these perspectives, I consider a sociological critique of ‘health’, ‘disease’, ‘illness’ and ‘sickness’ perspectives on medicine-taking, and of pharmacy as a profession. I then propose an experiential learning approach, with an emphasis on developing reflexivity through affective learning. I follow this with an illustrative case study. Following a critical discourse analysis of student texts from the case study, I conclude that there is evidence that experiential learning may prove useful in developing pharmacy students’ reflexive competency to support the provision of pharmaceutical care to patients using chronic medications.
- Full Text:
- Date Issued: 2006
- Authors: Williams, Kevin
- Date: 2006
- Subjects: Chronic diseases -- Chemotherapy Chronically ill -- Care Pharmacy -- Study and teaching Pharmacy -- Practice Social medicine Health -- Sociological aspects Diseases -- Sociological aspects Health -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1322 , http://hdl.handle.net/10962/d1003955
- Description: This study originates from experiences which led me to question the way pharmacists are equipped to advise and support the medicine-taking practice of patients using chronic medication. The study offers a critical theoretical consideration of underlying perspectives informing pharmacy education. I propose following a critical realist ontological perspective, a social realist understanding of social structure and human agency, and a sociocultural epistemology. Based on these perspectives, I consider a sociological critique of ‘health’, ‘disease’, ‘illness’ and ‘sickness’ perspectives on medicine-taking, and of pharmacy as a profession. I then propose an experiential learning approach, with an emphasis on developing reflexivity through affective learning. I follow this with an illustrative case study. Following a critical discourse analysis of student texts from the case study, I conclude that there is evidence that experiential learning may prove useful in developing pharmacy students’ reflexive competency to support the provision of pharmaceutical care to patients using chronic medications.
- Full Text:
- Date Issued: 2006
Using four different methods to reach a taxonomic conclusion in dung beetles (Scarabaeinae)
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
Using gene shuffling to increase genetic diversity in genes involved in beta-lactam biosynthesis
- Authors: Tarr, Shahida
- Date: 2001
- Subjects: Beta lactam antibiotics , Genes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4014 , http://hdl.handle.net/10962/d1004074 , Beta lactam antibiotics , Genes
- Description: The actinomycetes are gram-positive bacteria that produce more than two-thirds of the known biologically active microbial natural products, including many commercially important antibiotics, anti-cancer agents, other pharmacologically useful agents, animal health products and agrochemicals. The prevailing utilization of antibiotics continues to be the mainstay against microbial infections and a majority ofthe over six thousand antibiotics discovered thus far are from Streptomyces spp. One of the most well-characterized antibiotic biosynthetic pathway is the one involving the biosynthesis of the penicillins, cephalosporins and cephamycins. This pathway involves two initial steps which are common in filamentous fungi, lower eukaryotes and prokaryotes. The penam nucleus of penicillins and the cephem nucleus of both cephamycins andcephalosporins are formed by the condensation of the three precursor amino acids L-a-aminoadipic acid, Lcysteine and L-valine by a mechanism designated as 'non-ribosomal peptide synthesis', which involves activation and condensation of the three component amino acids and epimerization of the L- to D-valine to form a linear acyclic tripeptide called o-(L-a-aminoadipyl)-L-cysteinyl-Dvaline (ACV) by the action of a peptide synthetase. ACV is then cyclized to form isopenicillin N, an intermediate that contains an L-a-aminoadipyl side-chain attached to the penem nucleus (Fig. 1.2) by isopenicilin N synthase (IPNS or Cyclase) and this encompasses the creation of the Beta-lactam and thiazolidine rings. A broad range of ~-lactam producing Streptomyces spp were grown, the DNA extraction procedure optimised and total chromosomal DNA isolated. A bioinformatics analysis of known IPNS gene sequences allowed the synthesis of PCR primers for the iso-penicillin N synthase gene. IPNS genes and lPNS-like genes were successfully amplified from the total DNA of ten strains including two novel thermophilic strains, A. and B. Sequencing was carried out on the genes from S. hygroscopicus, S. tanashiensis and the two thermophiles A and B. This allowed development of the conditions for gene shuffiing of the IPNS gene which was carried out pairwise and resulted in the reconstitution of shuffied genes of the correct size. The resulting mixed gene sequences were cloned into the pTrcHis2-TOPO expression vector and the plasmid DNA screened and assayed for IPNS activity using HPLC which showed ten fold increase in IPNS activity as a result of the shuffiing.
- Full Text:
- Date Issued: 2001
- Authors: Tarr, Shahida
- Date: 2001
- Subjects: Beta lactam antibiotics , Genes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4014 , http://hdl.handle.net/10962/d1004074 , Beta lactam antibiotics , Genes
- Description: The actinomycetes are gram-positive bacteria that produce more than two-thirds of the known biologically active microbial natural products, including many commercially important antibiotics, anti-cancer agents, other pharmacologically useful agents, animal health products and agrochemicals. The prevailing utilization of antibiotics continues to be the mainstay against microbial infections and a majority ofthe over six thousand antibiotics discovered thus far are from Streptomyces spp. One of the most well-characterized antibiotic biosynthetic pathway is the one involving the biosynthesis of the penicillins, cephalosporins and cephamycins. This pathway involves two initial steps which are common in filamentous fungi, lower eukaryotes and prokaryotes. The penam nucleus of penicillins and the cephem nucleus of both cephamycins andcephalosporins are formed by the condensation of the three precursor amino acids L-a-aminoadipic acid, Lcysteine and L-valine by a mechanism designated as 'non-ribosomal peptide synthesis', which involves activation and condensation of the three component amino acids and epimerization of the L- to D-valine to form a linear acyclic tripeptide called o-(L-a-aminoadipyl)-L-cysteinyl-Dvaline (ACV) by the action of a peptide synthetase. ACV is then cyclized to form isopenicillin N, an intermediate that contains an L-a-aminoadipyl side-chain attached to the penem nucleus (Fig. 1.2) by isopenicilin N synthase (IPNS or Cyclase) and this encompasses the creation of the Beta-lactam and thiazolidine rings. A broad range of ~-lactam producing Streptomyces spp were grown, the DNA extraction procedure optimised and total chromosomal DNA isolated. A bioinformatics analysis of known IPNS gene sequences allowed the synthesis of PCR primers for the iso-penicillin N synthase gene. IPNS genes and lPNS-like genes were successfully amplified from the total DNA of ten strains including two novel thermophilic strains, A. and B. Sequencing was carried out on the genes from S. hygroscopicus, S. tanashiensis and the two thermophiles A and B. This allowed development of the conditions for gene shuffiing of the IPNS gene which was carried out pairwise and resulted in the reconstitution of shuffied genes of the correct size. The resulting mixed gene sequences were cloned into the pTrcHis2-TOPO expression vector and the plasmid DNA screened and assayed for IPNS activity using HPLC which showed ten fold increase in IPNS activity as a result of the shuffiing.
- Full Text:
- Date Issued: 2001
Using HIV/AIDS interventionist research in a university context to improve women’s sexual and reproductive health awareness
- Authors: Kidia, Nitasha
- Date: 2020
- Subjects: HIV infections -- Prevention -- South Africa , AIDS (Disease) -- Prevention -- South Africa , AIDS (Disease) -- Study and teaching -- South Africa , Health education (Higher) -- South Africa , Sex instruction -- South Africa , College students -- Sexual behavior -- South Africa , Sex instruction for women -- South Africa , Women college students -- Psychology -- South Africa , Women -- Health and hygiene -- South Africa , Women -- Diseases -- Prevention -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/165743 , vital:41277
- Description: Background: Young women in South Africa are a vulnerable group, with HIV prevalence almost twice that of men, limited preventive behaviour, and many challenges in negotiating sex. However, there is a paucity of in-depth research to understand how these challenges play out and what can be done to promote positive sexual and reproductive health in this population. Methods: To understand the effects of the Auntie Stella Activity card intervention (developed and used in Zimbabwe), this study used a mixed methods participatory action research design. Five focus group discussions among female Rhodes University students between the ages of 18- 23 were conducted with the activity cards as a basis for engagement. Additionally, pre-and postintervention sexual and reproductive health awareness levels were also measured by a customized questionnaire. Based on participants’ responses to the cards and post-exposure reflections on their learning, possible impacts on behaviour change were explored. Thematic analysis of transcripts was used to draw out major themes in the qualitative data. Results and conclusions: Themes that emerged were: 1) women’s self-esteem; 2) lack of knowledge; 3) peer pressure and male dominance; and 4) alcohol and substance use. Results of the pre- and post- intervention questionnaire found a positive change in knowledge and behaviour amongst the participants. However, the intervention in its current format focused too much on teenage rather than adult scenarios. To make it more useful for this population, further modifications that account for the target age group are needed. Overall, the challenges in sexual and reproductive health faced by university-aged women in South Africa are deeply concerning, but this study’s findings show that an intervention like the ASAC has the potential to be used widely in Southern Africa, if appropriately tailored.
- Full Text:
- Date Issued: 2020
- Authors: Kidia, Nitasha
- Date: 2020
- Subjects: HIV infections -- Prevention -- South Africa , AIDS (Disease) -- Prevention -- South Africa , AIDS (Disease) -- Study and teaching -- South Africa , Health education (Higher) -- South Africa , Sex instruction -- South Africa , College students -- Sexual behavior -- South Africa , Sex instruction for women -- South Africa , Women college students -- Psychology -- South Africa , Women -- Health and hygiene -- South Africa , Women -- Diseases -- Prevention -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/165743 , vital:41277
- Description: Background: Young women in South Africa are a vulnerable group, with HIV prevalence almost twice that of men, limited preventive behaviour, and many challenges in negotiating sex. However, there is a paucity of in-depth research to understand how these challenges play out and what can be done to promote positive sexual and reproductive health in this population. Methods: To understand the effects of the Auntie Stella Activity card intervention (developed and used in Zimbabwe), this study used a mixed methods participatory action research design. Five focus group discussions among female Rhodes University students between the ages of 18- 23 were conducted with the activity cards as a basis for engagement. Additionally, pre-and postintervention sexual and reproductive health awareness levels were also measured by a customized questionnaire. Based on participants’ responses to the cards and post-exposure reflections on their learning, possible impacts on behaviour change were explored. Thematic analysis of transcripts was used to draw out major themes in the qualitative data. Results and conclusions: Themes that emerged were: 1) women’s self-esteem; 2) lack of knowledge; 3) peer pressure and male dominance; and 4) alcohol and substance use. Results of the pre- and post- intervention questionnaire found a positive change in knowledge and behaviour amongst the participants. However, the intervention in its current format focused too much on teenage rather than adult scenarios. To make it more useful for this population, further modifications that account for the target age group are needed. Overall, the challenges in sexual and reproductive health faced by university-aged women in South Africa are deeply concerning, but this study’s findings show that an intervention like the ASAC has the potential to be used widely in Southern Africa, if appropriately tailored.
- Full Text:
- Date Issued: 2020
Using reading to learn pedagogy to enhance the English first additional language teachers’ classroom practice
- Authors: Mawela, Rethabile Rejoice
- Date: 2018
- Subjects: Reading to learn , Language transfer (Language learning) -- South Africa -- Kuruman , Language teachers -- South Africa -- Kuruman , Language and languages -- Study and teaching -- Bilingual method , Second language acquisition
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63415 , vital:28409
- Description: Drawing from the Hallidayan, Bernsteinian and Vygotskyan theories of Systemic Functional Linguistics, Pedagogic Discourse and Social Learning, this study examined the role that Rose's (2005) Reading to Learn (RtL) pedagogy could play in the development of teachers’ pedagogic practices in the teaching of English First Additional Language. The study participants teach English First Additional Language in Black, materially and economically disadvantaged rural primary schools in Kuruman, the Northern Cape Province, South Africa. As study participants, 4 intermediate phase and 4 senior phase teachers of English First Additional Language were purposively selected from 6 rural schools. Located within the Critical Paradigm, Subjective Epistemology and Mixed-Method approach, the study used documentary evidence, semi- structured interviews and RtL pedagogy as research instruments. Research findings reveal that RtL enriched and advanced teachers’ pedagogic practice in the teaching of reading and writing. As a consequence, teachers’ classroom practice of the 8 study participants improved as evidenced as their content knowledge expanded, the quality of teaching developed and their perceptions of themselves as professionals was transformed. An accompanying finding is that teachers acquired the tools to teach reading and the reading and writing proficiencies of learners in their classrooms improved.
- Full Text:
- Date Issued: 2018
- Authors: Mawela, Rethabile Rejoice
- Date: 2018
- Subjects: Reading to learn , Language transfer (Language learning) -- South Africa -- Kuruman , Language teachers -- South Africa -- Kuruman , Language and languages -- Study and teaching -- Bilingual method , Second language acquisition
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63415 , vital:28409
- Description: Drawing from the Hallidayan, Bernsteinian and Vygotskyan theories of Systemic Functional Linguistics, Pedagogic Discourse and Social Learning, this study examined the role that Rose's (2005) Reading to Learn (RtL) pedagogy could play in the development of teachers’ pedagogic practices in the teaching of English First Additional Language. The study participants teach English First Additional Language in Black, materially and economically disadvantaged rural primary schools in Kuruman, the Northern Cape Province, South Africa. As study participants, 4 intermediate phase and 4 senior phase teachers of English First Additional Language were purposively selected from 6 rural schools. Located within the Critical Paradigm, Subjective Epistemology and Mixed-Method approach, the study used documentary evidence, semi- structured interviews and RtL pedagogy as research instruments. Research findings reveal that RtL enriched and advanced teachers’ pedagogic practice in the teaching of reading and writing. As a consequence, teachers’ classroom practice of the 8 study participants improved as evidenced as their content knowledge expanded, the quality of teaching developed and their perceptions of themselves as professionals was transformed. An accompanying finding is that teachers acquired the tools to teach reading and the reading and writing proficiencies of learners in their classrooms improved.
- Full Text:
- Date Issued: 2018
Using risk mitigation approaches to define the requirements for software escrow
- Authors: Rode, Karl
- Date: 2015
- Subjects: Escrows , Source code (Computer Science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4714 , http://hdl.handle.net/10962/d1017936
- Description: Two or more parties entering into a contract for service or goods may make use of an escrow of the funds for payment to enable trust in the contract. In such an event the documents or financial instruments, the object(s) in escrow, are held in trust by a trusted third party (escrow provider) until the specified conditions are fulfilled. In the scenario of software escrow, the object of escrow is typically the source code, and the specified release conditions usually address potential scenarios wherein the software provider becomes unable to continue providing services (such as due to bankruptcy or a change in services provided, etc.) The subject of software escrow is not well documented in the academic body of work, with the largest information sources, active commentary and supporting papers provided by commercial software escrow providers, both in South Africa and abroad. This work maps the software escrow topic onto the King III compliance framework in South Africa. This is of value since any users of bespoke developed applications may require extended professional assistance to align with the King III guidelines. The supporting risk assessment model developed in this work will serve as a tool to evaluate and motivate for software escrow agreements. It will also provide an overview of the various escrow agreement types and will transfer the focus to the value proposition that they each hold. Initial research has indicated that current awareness of software escrow in industry is still very low. This was evidenced by the significant number of approached specialists that declined to participate in the survey due to their own admitted inexperience in applying the discipline of software escrow within their companies. Moreover, the participants that contributed to the research indicated that they only required software escrow for medium to highly critical applications. This proved the value of assessing the various risk factors that bespoke software development introduces, as well as the risk mitigation options available, through tools such as escrow, to reduce the actual and residual risk to a manageable level.
- Full Text:
- Date Issued: 2015
- Authors: Rode, Karl
- Date: 2015
- Subjects: Escrows , Source code (Computer Science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4714 , http://hdl.handle.net/10962/d1017936
- Description: Two or more parties entering into a contract for service or goods may make use of an escrow of the funds for payment to enable trust in the contract. In such an event the documents or financial instruments, the object(s) in escrow, are held in trust by a trusted third party (escrow provider) until the specified conditions are fulfilled. In the scenario of software escrow, the object of escrow is typically the source code, and the specified release conditions usually address potential scenarios wherein the software provider becomes unable to continue providing services (such as due to bankruptcy or a change in services provided, etc.) The subject of software escrow is not well documented in the academic body of work, with the largest information sources, active commentary and supporting papers provided by commercial software escrow providers, both in South Africa and abroad. This work maps the software escrow topic onto the King III compliance framework in South Africa. This is of value since any users of bespoke developed applications may require extended professional assistance to align with the King III guidelines. The supporting risk assessment model developed in this work will serve as a tool to evaluate and motivate for software escrow agreements. It will also provide an overview of the various escrow agreement types and will transfer the focus to the value proposition that they each hold. Initial research has indicated that current awareness of software escrow in industry is still very low. This was evidenced by the significant number of approached specialists that declined to participate in the survey due to their own admitted inexperience in applying the discipline of software escrow within their companies. Moreover, the participants that contributed to the research indicated that they only required software escrow for medium to highly critical applications. This proved the value of assessing the various risk factors that bespoke software development introduces, as well as the risk mitigation options available, through tools such as escrow, to reduce the actual and residual risk to a manageable level.
- Full Text:
- Date Issued: 2015
Using semantic knowledge to improve compression on log files
- Authors: Otten, Frederick John
- Date: 2009 , 2008-11-19
- Subjects: Computer networks , Data compression (Computer science) , Semantics--Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4650 , http://hdl.handle.net/10962/d1006619 , Computer networks , Data compression (Computer science) , Semantics--Data processing
- Description: With the move towards global and multi-national companies, information technology infrastructure requirements are increasing. As the size of these computer networks increases, it becomes more and more difficult to monitor, control, and secure them. Networks consist of a number of diverse devices, sensors, and gateways which are often spread over large geographical areas. Each of these devices produce log files which need to be analysed and monitored to provide network security and satisfy regulations. Data compression programs such as gzip and bzip2 are commonly used to reduce the quantity of data for archival purposes after the log files have been rotated. However, there are many other compression programs which exist - each with their own advantages and disadvantages. These programs each use a different amount of memory and take different compression and decompression times to achieve different compression ratios. System log files also contain redundancy which is not necessarily exploited by standard compression programs. Log messages usually use a similar format with a defined syntax. In the log files, all the ASCII characters are not used and the messages contain certain "phrases" which often repeated. This thesis investigates the use of compression as a means of data reduction and how the use of semantic knowledge can improve data compression (also applying results to different scenarios that can occur in a distributed computing environment). It presents the results of a series of tests performed on different log files. It also examines the semantic knowledge which exists in maillog files and how it can be exploited to improve the compression results. The results from a series of text preprocessors which exploit this knowledge are presented and evaluated. These preprocessors include: one which replaces the timestamps and IP addresses with their binary equivalents and one which replaces words from a dictionary with unused ASCII characters. In this thesis, data compression is shown to be an effective method of data reduction producing up to 98 percent reduction in filesize on a corpus of log files. The use of preprocessors which exploit semantic knowledge results in up to 56 percent improvement in overall compression time and up to 32 percent reduction in compressed size. , TeX , pdfTeX-1.40.3
- Full Text:
- Date Issued: 2009
- Authors: Otten, Frederick John
- Date: 2009 , 2008-11-19
- Subjects: Computer networks , Data compression (Computer science) , Semantics--Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4650 , http://hdl.handle.net/10962/d1006619 , Computer networks , Data compression (Computer science) , Semantics--Data processing
- Description: With the move towards global and multi-national companies, information technology infrastructure requirements are increasing. As the size of these computer networks increases, it becomes more and more difficult to monitor, control, and secure them. Networks consist of a number of diverse devices, sensors, and gateways which are often spread over large geographical areas. Each of these devices produce log files which need to be analysed and monitored to provide network security and satisfy regulations. Data compression programs such as gzip and bzip2 are commonly used to reduce the quantity of data for archival purposes after the log files have been rotated. However, there are many other compression programs which exist - each with their own advantages and disadvantages. These programs each use a different amount of memory and take different compression and decompression times to achieve different compression ratios. System log files also contain redundancy which is not necessarily exploited by standard compression programs. Log messages usually use a similar format with a defined syntax. In the log files, all the ASCII characters are not used and the messages contain certain "phrases" which often repeated. This thesis investigates the use of compression as a means of data reduction and how the use of semantic knowledge can improve data compression (also applying results to different scenarios that can occur in a distributed computing environment). It presents the results of a series of tests performed on different log files. It also examines the semantic knowledge which exists in maillog files and how it can be exploited to improve the compression results. The results from a series of text preprocessors which exploit this knowledge are presented and evaluated. These preprocessors include: one which replaces the timestamps and IP addresses with their binary equivalents and one which replaces words from a dictionary with unused ASCII characters. In this thesis, data compression is shown to be an effective method of data reduction producing up to 98 percent reduction in filesize on a corpus of log files. The use of preprocessors which exploit semantic knowledge results in up to 56 percent improvement in overall compression time and up to 32 percent reduction in compressed size. , TeX , pdfTeX-1.40.3
- Full Text:
- Date Issued: 2009
Using the indigenous technology of dyeing and weaving African baskets as a cultural tool to mediate learning of chemical and physical changes
- Authors: Kakambi, William Mafelezo
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Chemistry -- Study and teaching (Secondary) -- Namibia , Ethnoscience -- Namibia , Culturally relevant pedagogy , Traditional ecological knowledge -- Namibia , Basket making -- Namibia , Dyes and dyeing -- Namibia , Pedagogical content knowledge
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177268 , vital:42805
- Description: Literature has revealed that indigenous learners, especially in many African nations are subjected to learning school science in unfamiliar contexts. Learners in Namibia where this study was conducted are no exception. In consequence, learners experience cognitive conflict between school science and the experiences learnt at home and in the community. This is exacerbated, in part, by the fact that science teachers do not seem to know how to integrate indigenous knowledge in their science teaching. As an attempt to address this problem, some scholars call for the integration of indigenous knowledge into the science curriculum to provide a much needed context for learning science. It is against this background that this study sought to use the indigenous technology of dyeing and weaving baskets as a cultural tool to mediate learning of chemical and physical changes. Underpinned by the interpretivist and Ubuntu paradigms, the study employed a qualitative case study research design. The study was conducted in the Zambezi region in Namibia. Four grade 8 Physical Science teachers, an expert community member, and a critical friend were involved as participants in this study. Data were gathered using semi-structured interviews, workshop discussions, participatory observation, and journal reflections. Vygotsky’s socio-cultural theory and Mavhunga and Rollnick’s topic specific pedagogical content knowledge were used as theoretical and analytical frameworks, respectively. A thematic approach to data analysis was employed to come up with sub-themes and themes. The findings of the study revealed that all the participating teachers in this study had never been exposed to ideas on how to integrate indigenous knowledge in their science teaching. As a result, they all embraced and valued the indigenous technology of dyeing and weaving as relevant and useful in the teaching and learning of chemical and physical changes. This study recommends that there is a need to empower science teachers on how to integrate indigenous knowledge in their science teaching in order to make science accessible and relevant to their learners’ lived worlds. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Kakambi, William Mafelezo
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Chemistry -- Study and teaching (Secondary) -- Namibia , Ethnoscience -- Namibia , Culturally relevant pedagogy , Traditional ecological knowledge -- Namibia , Basket making -- Namibia , Dyes and dyeing -- Namibia , Pedagogical content knowledge
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177268 , vital:42805
- Description: Literature has revealed that indigenous learners, especially in many African nations are subjected to learning school science in unfamiliar contexts. Learners in Namibia where this study was conducted are no exception. In consequence, learners experience cognitive conflict between school science and the experiences learnt at home and in the community. This is exacerbated, in part, by the fact that science teachers do not seem to know how to integrate indigenous knowledge in their science teaching. As an attempt to address this problem, some scholars call for the integration of indigenous knowledge into the science curriculum to provide a much needed context for learning science. It is against this background that this study sought to use the indigenous technology of dyeing and weaving baskets as a cultural tool to mediate learning of chemical and physical changes. Underpinned by the interpretivist and Ubuntu paradigms, the study employed a qualitative case study research design. The study was conducted in the Zambezi region in Namibia. Four grade 8 Physical Science teachers, an expert community member, and a critical friend were involved as participants in this study. Data were gathered using semi-structured interviews, workshop discussions, participatory observation, and journal reflections. Vygotsky’s socio-cultural theory and Mavhunga and Rollnick’s topic specific pedagogical content knowledge were used as theoretical and analytical frameworks, respectively. A thematic approach to data analysis was employed to come up with sub-themes and themes. The findings of the study revealed that all the participating teachers in this study had never been exposed to ideas on how to integrate indigenous knowledge in their science teaching. As a result, they all embraced and valued the indigenous technology of dyeing and weaving as relevant and useful in the teaching and learning of chemical and physical changes. This study recommends that there is a need to empower science teachers on how to integrate indigenous knowledge in their science teaching in order to make science accessible and relevant to their learners’ lived worlds. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-04
Using the indigenous technology of making oshikundu to mediate learning of the topic diffusion in Namibia
- Authors: Endjala, Alma Panduleni
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419726 , vital:71670
- Description: The Namibian Science curriculum acknowledges that indigenous knowledge (IK) is an important basis for learning science. Among the shared reasons is that it provides learners with access to abstract scientific concepts. As a result, teachers are encouraged to integrate IK into the teaching and learning of science. However, it seems that there are no explicit guidelines on how IK should be integrated into science classrooms. It is against this backdrop that this study sought to explore how the indigenous technology of making oshikundu (a non-alcoholic beverage) can be mobilised by Grade 8 Life Science teachers to mediate learning of diffusion in their classrooms. The study was underpinned by interpretive and indigenous research paradigms. Within these paradigms, a qualitative case study approach was employed. Four Grade 8 Life Science teachers from four different schools in Okahandja town, Otjozondjupa Region, Namibia, participated in this study. Additionally, an expert community member who was knowledgeable about the indigenous technology of making oshikundu was requested to demonstrate how to make it. In this event, the Life Science teachers had to identify the science concepts embedded in the practice. To gather data, this study made use of semi-structured interviews, workshop discussions, observations and journal reflections. Vygotsky’s sociocultural theory was used as a theoretical framework and Mavhunga and Rollnick’s topic-specific pedagogical content knowledge (TSPCK) was used as an analytical framework. The findings of this study revealed that the teachers’ understanding was positively influenced by the integration of IK which certainly assisted them to relate better to the concept of diffusion. This was validated when teachers extracted emerging science concepts from the indigenous technology of making oshikundu. The implication of this study is that expert community member presentations can greatly enhance sense making of science concepts. The study thus recommends that school-based teachers’ continuing professional development in collaboration with expert community members should be carried out to enhance both the teachers’ subject content knowledge and pedagogical content knowledge on IK integration. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Endjala, Alma Panduleni
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419726 , vital:71670
- Description: The Namibian Science curriculum acknowledges that indigenous knowledge (IK) is an important basis for learning science. Among the shared reasons is that it provides learners with access to abstract scientific concepts. As a result, teachers are encouraged to integrate IK into the teaching and learning of science. However, it seems that there are no explicit guidelines on how IK should be integrated into science classrooms. It is against this backdrop that this study sought to explore how the indigenous technology of making oshikundu (a non-alcoholic beverage) can be mobilised by Grade 8 Life Science teachers to mediate learning of diffusion in their classrooms. The study was underpinned by interpretive and indigenous research paradigms. Within these paradigms, a qualitative case study approach was employed. Four Grade 8 Life Science teachers from four different schools in Okahandja town, Otjozondjupa Region, Namibia, participated in this study. Additionally, an expert community member who was knowledgeable about the indigenous technology of making oshikundu was requested to demonstrate how to make it. In this event, the Life Science teachers had to identify the science concepts embedded in the practice. To gather data, this study made use of semi-structured interviews, workshop discussions, observations and journal reflections. Vygotsky’s sociocultural theory was used as a theoretical framework and Mavhunga and Rollnick’s topic-specific pedagogical content knowledge (TSPCK) was used as an analytical framework. The findings of this study revealed that the teachers’ understanding was positively influenced by the integration of IK which certainly assisted them to relate better to the concept of diffusion. This was validated when teachers extracted emerging science concepts from the indigenous technology of making oshikundu. The implication of this study is that expert community member presentations can greatly enhance sense making of science concepts. The study thus recommends that school-based teachers’ continuing professional development in collaboration with expert community members should be carried out to enhance both the teachers’ subject content knowledge and pedagogical content knowledge on IK integration. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
- Date Issued: 2023-10-13
Using the larval parasitoid, Agathis bishopi (Nixon) (Hymenoptera: Braconidae), for early detection of false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) infested fruit
- Authors: Zimba, Kennedy Josaya
- Date: 2015
- Subjects: Cryptophlebia leucotreta , Citrus -- Diseases and pests -- South Africa , Pests -- Biological control -- South Africa , Cryptophlebia leucotreta -- Detection , Parasitoids -- Hosts , Braconidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5919 , http://hdl.handle.net/10962/d1017186
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is one of the major citrus pests of economic importance for South Africa’s citrus industry. It is endemic to Africa, and therefore a phytosanitary pest with zero tolerance by most export markets. The cryptic nature of T. leucotreta makes visual inspection an inefficient method for detecting neonate larvae in fruit in the packhouse. Therefore, a more accurate method for sorting infested fruit at the packhouse, particularly for newly infested fruit could ensure market access. A recent study showed that fruit infested by T. leucotreta emit a chemical profile different from that of a healthy fruit. Several studies provide evidence that parasitoids locate their hosts feeding on fruit by exploiting the novel chemical profiles produced due to host herbivory. The aim of this study was to evaluate the potential of using the naturally occurring behaviour of a larval parasitoid Agathis bishopi (Nixon) (Hymenoptera: Braconidae) for detection of T. leucotreta infested fruit, by determining which compound in infested fruit is attractive to parasitoids. Ytube olfactometer and flight-tunnel bioassays with healthy and T. leucotreta infested fruit showed a significantly stronger response of A. bishopi female parasitoids to infested fruit. Among the volatile compounds associated with T. leucotreta infested fruit, D-limonene elicited the strongest attraction to A. bishopi female parasitoids. Attraction of mated A. bishopi female parasitoids to T. leucotreta infested fruit and D-limonene significantly increased after oviposition experience. Behavioural responses of A. bishopi female parasitoids that were associated with T. leucotreta infested fruit were investigated to determine which behaviours are distinct and interpretable. Probing and oviposition behaviours were the most noticeable and were only elicited on infested fruit when parasitoids contacted T. leucotreta frass, indicating that chemical compounds in frass are short-range cues used for final host location. Since production of D-limonene by fruit is elevated due to herbivory by different pests including mechanical injury on fruit, response of A. bishopi female parasitoids to compounds in frass offers a more specific and potentially useful mechanism for development of a detection system for T. leucotreta infested fruit. Chemical analysis of T. leucotreta frass and conditioning A. bishopi parasitoids to respond behaviourally to compounds in frass is proposed.
- Full Text:
- Date Issued: 2015
- Authors: Zimba, Kennedy Josaya
- Date: 2015
- Subjects: Cryptophlebia leucotreta , Citrus -- Diseases and pests -- South Africa , Pests -- Biological control -- South Africa , Cryptophlebia leucotreta -- Detection , Parasitoids -- Hosts , Braconidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5919 , http://hdl.handle.net/10962/d1017186
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is one of the major citrus pests of economic importance for South Africa’s citrus industry. It is endemic to Africa, and therefore a phytosanitary pest with zero tolerance by most export markets. The cryptic nature of T. leucotreta makes visual inspection an inefficient method for detecting neonate larvae in fruit in the packhouse. Therefore, a more accurate method for sorting infested fruit at the packhouse, particularly for newly infested fruit could ensure market access. A recent study showed that fruit infested by T. leucotreta emit a chemical profile different from that of a healthy fruit. Several studies provide evidence that parasitoids locate their hosts feeding on fruit by exploiting the novel chemical profiles produced due to host herbivory. The aim of this study was to evaluate the potential of using the naturally occurring behaviour of a larval parasitoid Agathis bishopi (Nixon) (Hymenoptera: Braconidae) for detection of T. leucotreta infested fruit, by determining which compound in infested fruit is attractive to parasitoids. Ytube olfactometer and flight-tunnel bioassays with healthy and T. leucotreta infested fruit showed a significantly stronger response of A. bishopi female parasitoids to infested fruit. Among the volatile compounds associated with T. leucotreta infested fruit, D-limonene elicited the strongest attraction to A. bishopi female parasitoids. Attraction of mated A. bishopi female parasitoids to T. leucotreta infested fruit and D-limonene significantly increased after oviposition experience. Behavioural responses of A. bishopi female parasitoids that were associated with T. leucotreta infested fruit were investigated to determine which behaviours are distinct and interpretable. Probing and oviposition behaviours were the most noticeable and were only elicited on infested fruit when parasitoids contacted T. leucotreta frass, indicating that chemical compounds in frass are short-range cues used for final host location. Since production of D-limonene by fruit is elevated due to herbivory by different pests including mechanical injury on fruit, response of A. bishopi female parasitoids to compounds in frass offers a more specific and potentially useful mechanism for development of a detection system for T. leucotreta infested fruit. Chemical analysis of T. leucotreta frass and conditioning A. bishopi parasitoids to respond behaviourally to compounds in frass is proposed.
- Full Text:
- Date Issued: 2015
Using the local environment for outcomes-based education: issues raised for INSET by teachers' perceptions of agents of change
- Authors: Burton, Noreen
- Date: 1998
- Subjects: In-service education and training for teachers Teachers -- Training of -- South Africa Teachers -- In-service training -- South Africa Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1818 , http://hdl.handle.net/10962/d1003704
- Description: South African education is in the process of undergoing what has become known as a "paradigm shift", requiring a change from the familiar transmission method to outcomes-based education (OBE) founded on social constructivist theories oflearning and teaching. Teachers, (45% of whom are poorly qualified), "will play a pivotal role in the success or failure of this change. There is therefore an urgent need to re-educate in-service teachers in the philosophy, and related methodologies underpinning Curriculum 2005. To this end, in-service education courses need to be developed "which will encourage teachers to reconstruct their beliefs about teaching and learning. INSET programmes in the past were aimed at either "topping up" qualified teachers, or "adding on" for under qualified teachers - neither of which have proved successful. It is therefore unlikely that applying similar methodologies to support teachers in the shift to OBE will meet with success, nor will simply "training" teachers to use the new learning programmes. Government documents on Education Policy are calling for teachers to become reflexive practitioners, able to guide learners in their efforts to achieve the critical outcomes which are intended to develop a competent citizenry of lifelong learners. Therefore, teachers ought to be empowered as curriculum developers in their own right. This interpretative case study hoped to find out from teachers themselves what aspects of an activity-based environmental education course acted as change agents in assisting them to begin the shift to constructivist theories of teaching and learning. A variety of research tools were used, including questionnaires, interviews, journals, narratives and concept maps, all of which provided a rich source of data for interpretation. From what was gained from four participants in this research, tentative suggestions for incorporation into the next cycle of action research in future INSET programmes are made.
- Full Text:
- Date Issued: 1998
- Authors: Burton, Noreen
- Date: 1998
- Subjects: In-service education and training for teachers Teachers -- Training of -- South Africa Teachers -- In-service training -- South Africa Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1818 , http://hdl.handle.net/10962/d1003704
- Description: South African education is in the process of undergoing what has become known as a "paradigm shift", requiring a change from the familiar transmission method to outcomes-based education (OBE) founded on social constructivist theories oflearning and teaching. Teachers, (45% of whom are poorly qualified), "will play a pivotal role in the success or failure of this change. There is therefore an urgent need to re-educate in-service teachers in the philosophy, and related methodologies underpinning Curriculum 2005. To this end, in-service education courses need to be developed "which will encourage teachers to reconstruct their beliefs about teaching and learning. INSET programmes in the past were aimed at either "topping up" qualified teachers, or "adding on" for under qualified teachers - neither of which have proved successful. It is therefore unlikely that applying similar methodologies to support teachers in the shift to OBE will meet with success, nor will simply "training" teachers to use the new learning programmes. Government documents on Education Policy are calling for teachers to become reflexive practitioners, able to guide learners in their efforts to achieve the critical outcomes which are intended to develop a competent citizenry of lifelong learners. Therefore, teachers ought to be empowered as curriculum developers in their own right. This interpretative case study hoped to find out from teachers themselves what aspects of an activity-based environmental education course acted as change agents in assisting them to begin the shift to constructivist theories of teaching and learning. A variety of research tools were used, including questionnaires, interviews, journals, narratives and concept maps, all of which provided a rich source of data for interpretation. From what was gained from four participants in this research, tentative suggestions for incorporation into the next cycle of action research in future INSET programmes are made.
- Full Text:
- Date Issued: 1998
Using the topic "Water management in Umtata" to promote the use of an environmental approach in the teaching of geography
- Authors: Nduna, Joyce Nothemba
- Date: 1995
- Subjects: Geography -- Study and teaching -- Environmental aspects Water -- Management -- Study and teaching -- Environmental aspects Environmental education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1819 , http://hdl.handle.net/10962/d1003705
- Description: This study first offers a critique of some conventional approaches to environmental education and geography. The critique is followed by an analysis of current learning theories which underpin environmental and geographical thinking. On the basis of this analysis an environmental approach to the teaching of geography is identified. Within the broad theoretical context provided by debates on the importance of environmental education for the solution of environmental problems, the study promotes student teachers' understanding of an environmental approach in the teaching of geography at Transkei College of Education. Water management, a section of the geography syllabus, is selected to illustrate the process and implementation of such an approach in geography. The educational effectiveness of an environmental approach with regard to the students' conceptual understanding of water management is evaluated. The study as a whole is set within the general literature of environmental education, and particularly that of education for the environment.
- Full Text:
- Date Issued: 1995
- Authors: Nduna, Joyce Nothemba
- Date: 1995
- Subjects: Geography -- Study and teaching -- Environmental aspects Water -- Management -- Study and teaching -- Environmental aspects Environmental education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1819 , http://hdl.handle.net/10962/d1003705
- Description: This study first offers a critique of some conventional approaches to environmental education and geography. The critique is followed by an analysis of current learning theories which underpin environmental and geographical thinking. On the basis of this analysis an environmental approach to the teaching of geography is identified. Within the broad theoretical context provided by debates on the importance of environmental education for the solution of environmental problems, the study promotes student teachers' understanding of an environmental approach in the teaching of geography at Transkei College of Education. Water management, a section of the geography syllabus, is selected to illustrate the process and implementation of such an approach in geography. The educational effectiveness of an environmental approach with regard to the students' conceptual understanding of water management is evaluated. The study as a whole is set within the general literature of environmental education, and particularly that of education for the environment.
- Full Text:
- Date Issued: 1995
Using the van Hiele theory to analyse geometrical conceptualisation in grade 12 students: a Namibian perspective
- Authors: Mateya, Muhongo
- Date: 2009
- Subjects: Hiele, Pierre M. van Hiele-Geldof, Dina van Geometry -- Study and teaching (Secondary) -- Namibia Mathematics -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1820 , http://hdl.handle.net/10962/d1003706
- Description: The study reported here utilised a theory of levels of geometric thinking. This theory was proposed and developed by two Dutch mathematics educators, Pierre van Hiele and his wife, Dina van Hiele-Geldof. The van Hiele theory enables investigations into why many students experience difficulties in learning geometry. In many nations, such as the UK, the USA, Netherlands, the USSR and to a certain extent, Nigeria and South Africa, research evidence has indicated that the overall students’ mathematical competencies are linked to their geometric thinking levels. This study is the first of its kind to apply the van Hiele theory of geometric thinking in the Namibian context to analyse geometrical conceptualisation in Grade 12 mathematics students. In all, 50 Grade 12 students (20 from School A and 30 from School B) were involved in this study. These students wrote a van Hiele Geometry Test adapted from the Cognitive Development and Achievement in Secondary School Geometry test items. Thereafter, a clinical interview with the aid of manipulatives was conducted. The results from this study indicated that many of the School A and School B students who participated in the research have a weak conceptual understanding of geometric concepts: 35% of the School A and 40% of the School B subsamples were at the prerecognition level. 25% and 30% of the School A, and 20% and 23.3% of the School B students were at van Hiele levels 1 and 2 respectively. An equal number of students but different in percentages, 2 (10%) in School A and 2 (6.7%) in School B, were at van Hiele level 3. Only one student from School B attained van Hiele level 4. These results were found to be consistent with those of previous similar studies in UK, USA, Nigeria and South Africa. The findings of this study also highlight issues of how the Namibian Grade 12 geometry syllabus should be aligned with the van Hiele levels of geometric thinking as well as the use of appropriate and correct language in geometrical thinking and problem solving.
- Full Text:
- Date Issued: 2009
- Authors: Mateya, Muhongo
- Date: 2009
- Subjects: Hiele, Pierre M. van Hiele-Geldof, Dina van Geometry -- Study and teaching (Secondary) -- Namibia Mathematics -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1820 , http://hdl.handle.net/10962/d1003706
- Description: The study reported here utilised a theory of levels of geometric thinking. This theory was proposed and developed by two Dutch mathematics educators, Pierre van Hiele and his wife, Dina van Hiele-Geldof. The van Hiele theory enables investigations into why many students experience difficulties in learning geometry. In many nations, such as the UK, the USA, Netherlands, the USSR and to a certain extent, Nigeria and South Africa, research evidence has indicated that the overall students’ mathematical competencies are linked to their geometric thinking levels. This study is the first of its kind to apply the van Hiele theory of geometric thinking in the Namibian context to analyse geometrical conceptualisation in Grade 12 mathematics students. In all, 50 Grade 12 students (20 from School A and 30 from School B) were involved in this study. These students wrote a van Hiele Geometry Test adapted from the Cognitive Development and Achievement in Secondary School Geometry test items. Thereafter, a clinical interview with the aid of manipulatives was conducted. The results from this study indicated that many of the School A and School B students who participated in the research have a weak conceptual understanding of geometric concepts: 35% of the School A and 40% of the School B subsamples were at the prerecognition level. 25% and 30% of the School A, and 20% and 23.3% of the School B students were at van Hiele levels 1 and 2 respectively. An equal number of students but different in percentages, 2 (10%) in School A and 2 (6.7%) in School B, were at van Hiele level 3. Only one student from School B attained van Hiele level 4. These results were found to be consistent with those of previous similar studies in UK, USA, Nigeria and South Africa. The findings of this study also highlight issues of how the Namibian Grade 12 geometry syllabus should be aligned with the van Hiele levels of geometric thinking as well as the use of appropriate and correct language in geometrical thinking and problem solving.
- Full Text:
- Date Issued: 2009
Vachellia erioloba (camel thorn) and microbial interactions
- Authors: Van Aswegen, Sunet
- Date: 2018
- Subjects: Vesicular-arbuscular mycorrhizas , Cadmium , Rhizobacteria , Plant growth-promoting rhizobacteria , Acacia erioloba
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/63716 , vital:28475
- Description: Vachellia erioloba (camel thorn) is one of South Africa’s economically important tree species and therefore requires further investigation to improve its health and growth. Beneficial soil microbes have positive effects on plants through various mechanisms such as nitrogen fixation, phosphate solubilisation, indole acetic acid and siderophore production and biofilm formation. These traits enhance plant growth and protect the host plant against parasitic organisms that are present in soil. The arbuscular mycorrhizal (AM) fungi are well known for their beneficial symbiotic effects on host plants. The objective of this study was to determine the role of AM fungi and associated beneficial rhizobacteria in improving the growth of V. erioloba seedlings. Soil and root samples were collected from a farm in the Northern Cape, South Africa. Fifty-seven bacterial cultures were isolated from the soil and tested for plant growth promoting characteristics. Fourteen isolates showing at least four beneficial traits were molecularly identified using the GenBank database. The AM fungal and bacterial populations in the soil samples were assessed using Illumina sequencing. Sequences were identified using the MaarJAM and GenBank databases, respectively. Three separate pot trials were conducted to determine; 1) the effects of cadmium (Cd) on seedling growth; 2) the individual effects of three selected bacterial isolates and AM fungi alone and combined on seedling growth, and 3) the combined effects of the selected bacteria on AM fungal inoculated and uninoculated seedlings. Of the fourteen isolates the Enterobacter genera was the dominant species identified, with Acinetobacter, Pantoea and Bacillus each having one isolate. All were described as plant growth promoting rhizobacteria. One isolate from each genus, excluding Pantoea, was used in the pot trials. Three genera were identified in the AM fungal population that was assessed, namely Ambispora, Paraglomus and Glomus with Ambispora being the dominant genus. The bacterial population assessed showed a high diversity of bacteria from the Actinobacteria phylum being the dominant group. The results of the heavy metal pot trial showed that the symbiotic relationship between the seedlings and AM fungi increased the seedlings’ health and growth during heavy metal stress. The combination of bacteria and AM fungi increased growth parameters in all the inoculated seedlings, but not when compared to uninoculated seedlings indicating a possible competition for nutrients. The results were influenced by the presence of a nematode, which was suspected to have been seed borne. Further investigations on these interactions are required. Inoculation of AM fungi and selected PGPR is recommended for V. erioloba seedling production. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Van Aswegen, Sunet
- Date: 2018
- Subjects: Vesicular-arbuscular mycorrhizas , Cadmium , Rhizobacteria , Plant growth-promoting rhizobacteria , Acacia erioloba
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/63716 , vital:28475
- Description: Vachellia erioloba (camel thorn) is one of South Africa’s economically important tree species and therefore requires further investigation to improve its health and growth. Beneficial soil microbes have positive effects on plants through various mechanisms such as nitrogen fixation, phosphate solubilisation, indole acetic acid and siderophore production and biofilm formation. These traits enhance plant growth and protect the host plant against parasitic organisms that are present in soil. The arbuscular mycorrhizal (AM) fungi are well known for their beneficial symbiotic effects on host plants. The objective of this study was to determine the role of AM fungi and associated beneficial rhizobacteria in improving the growth of V. erioloba seedlings. Soil and root samples were collected from a farm in the Northern Cape, South Africa. Fifty-seven bacterial cultures were isolated from the soil and tested for plant growth promoting characteristics. Fourteen isolates showing at least four beneficial traits were molecularly identified using the GenBank database. The AM fungal and bacterial populations in the soil samples were assessed using Illumina sequencing. Sequences were identified using the MaarJAM and GenBank databases, respectively. Three separate pot trials were conducted to determine; 1) the effects of cadmium (Cd) on seedling growth; 2) the individual effects of three selected bacterial isolates and AM fungi alone and combined on seedling growth, and 3) the combined effects of the selected bacteria on AM fungal inoculated and uninoculated seedlings. Of the fourteen isolates the Enterobacter genera was the dominant species identified, with Acinetobacter, Pantoea and Bacillus each having one isolate. All were described as plant growth promoting rhizobacteria. One isolate from each genus, excluding Pantoea, was used in the pot trials. Three genera were identified in the AM fungal population that was assessed, namely Ambispora, Paraglomus and Glomus with Ambispora being the dominant genus. The bacterial population assessed showed a high diversity of bacteria from the Actinobacteria phylum being the dominant group. The results of the heavy metal pot trial showed that the symbiotic relationship between the seedlings and AM fungi increased the seedlings’ health and growth during heavy metal stress. The combination of bacteria and AM fungi increased growth parameters in all the inoculated seedlings, but not when compared to uninoculated seedlings indicating a possible competition for nutrients. The results were influenced by the presence of a nematode, which was suspected to have been seed borne. Further investigations on these interactions are required. Inoculation of AM fungi and selected PGPR is recommended for V. erioloba seedling production. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Valedictory address: Miss M.G Richardson
- Authors: Henderson, Derek Scott
- Date: 1983-06-06
- Language: English
- Type: Text
- Identifier: vital:7455 , http://hdl.handle.net/10962/d1018332
- Full Text:
- Date Issued: 1983-06-06
- Authors: Henderson, Derek Scott
- Date: 1983-06-06
- Language: English
- Type: Text
- Identifier: vital:7455 , http://hdl.handle.net/10962/d1018332
- Full Text:
- Date Issued: 1983-06-06